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1.
J Allergy Clin Immunol ; 147(1): 81-91, 2021 01.
Article in English | MEDLINE | ID: covidwho-2095538

ABSTRACT

BACKGROUND: Severe immunopathology may drive the deleterious manifestations that are observed in the advanced stages of coronavirus disease 2019 (COVID-19) but are poorly understood. OBJECTIVE: Our aim was to phenotype leukocyte subpopulations and the cytokine milieu in the lungs and blood of critically ill patients with COVID-19 acute respiratory distress syndrome (ARDS). METHODS: We consecutively included patients less than 72 hours after intubation following informed consent from their next of kin. Bronchoalveolar lavage fluid was evaluated by microscopy; bronchoalveolar lavage fluid and blood were assessed by 10-color flow cytometry and a multiplex cytokine panel. RESULTS: Four mechanically ventilated patients (aged 40-75 years) with moderate-to-severe COVID-19 ARDS were included. Immature neutrophils dominated in both blood and lungs, whereas CD4 and CD8 T-cell lymphopenia was observed in the 2 compartments. However, regulatory T cells and TH17 cells were found in higher fractions in the lung. Lung CD4 and CD8 T cells and macrophages expressed an even higher upregulation of activation markers than in blood. A wide range of cytokines were expressed at high levels both in the blood and in the lungs, most notably, IL-1RA, IL-6, IL-8, IP-10, and monocyte chemoattactant protein-1, consistent with hyperinflammation. CONCLUSION: COVID-19 ARDS exhibits a distinct immunologic profile in the lungs, with a depleted and exhausted CD4 and CD8 T-cell population that resides within a heavily hyperinflammatory milieu.


Subject(s)
CD8-Positive T-Lymphocytes/immunology , COVID-19/immunology , Lung/immunology , Lymphopenia/immunology , Respiratory Distress Syndrome/immunology , SARS-CoV-2/immunology , Th17 Cells/immunology , Adult , Aged , CD8-Positive T-Lymphocytes/pathology , COVID-19/pathology , Cross-Sectional Studies , Cytokines/immunology , Female , Humans , Immunophenotyping , Lung/pathology , Lymphopenia/pathology , Male , Middle Aged , Respiratory Distress Syndrome/pathology , Th17 Cells/pathology
2.
Nature ; 609(7928): 801-807, 2022 09.
Article in English | MEDLINE | ID: covidwho-1960390

ABSTRACT

Anorexia and fasting are host adaptations to acute infection, and induce a metabolic switch towards ketogenesis and the production of ketone bodies, including ß-hydroxybutyrate (BHB)1-6. However, whether ketogenesis metabolically influences the immune response in pulmonary infections remains unclear. Here we show that the production of BHB is impaired in individuals with SARS-CoV-2-induced acute respiratory distress syndrome (ARDS) but not in those with  influenza-induced ARDS. We found that BHB promotes both the survival of and the production of interferon-γ by CD4+ T cells. Applying a metabolic-tracing analysis, we established that BHB provides an alternative carbon source to fuel oxidative phosphorylation (OXPHOS) and the production of bioenergetic amino acids and glutathione, which is important for maintaining the redox balance. T cells from patients with SARS-CoV-2-induced ARDS were exhausted and skewed towards glycolysis, but could be metabolically reprogrammed by BHB to perform OXPHOS, thereby increasing their functionality. Finally, we show in mice that a ketogenic diet and the delivery of BHB as a ketone ester drink restores CD4+ T cell metabolism and function in severe respiratory infections, ultimately reducing the mortality of mice infected with SARS-CoV-2. Altogether, our data reveal that BHB is an alternative source of carbon that promotes T cell responses in pulmonary viral infections, and highlight impaired ketogenesis as a potential confounding factor in severe COVID-19.


Subject(s)
COVID-19 , Energy Metabolism , Ketones , Respiratory Distress Syndrome , SARS-CoV-2 , T-Lymphocytes , 3-Hydroxybutyric Acid/biosynthesis , 3-Hydroxybutyric Acid/metabolism , Amino Acids/biosynthesis , Amino Acids/metabolism , Animals , COVID-19/complications , COVID-19/immunology , COVID-19/pathology , Diet, Ketogenic , Esters/metabolism , Glutathione/biosynthesis , Glutathione/metabolism , Glycolysis , Interferon-gamma/biosynthesis , Ketone Bodies/metabolism , Ketones/metabolism , Mice , Orthomyxoviridae/pathogenicity , Oxidation-Reduction , Oxidative Phosphorylation , Respiratory Distress Syndrome/complications , Respiratory Distress Syndrome/immunology , Respiratory Distress Syndrome/metabolism , Respiratory Distress Syndrome/virology , SARS-CoV-2/pathogenicity , T-Lymphocytes/immunology , T-Lymphocytes/metabolism , T-Lymphocytes/pathology
3.
J Biomed Sci ; 29(1): 52, 2022 Jul 11.
Article in English | MEDLINE | ID: covidwho-1928188

ABSTRACT

BACKGROUND: Coronavirus-induced disease 19 (COVID-19) infects more than three hundred and sixty million patients worldwide, and people with severe symptoms frequently die of acute respiratory distress syndrome (ARDS). Recent studies indicated that excessive neutrophil extracellular traps (NETs) contributed to immunothrombosis, thereby leading to extensive intravascular coagulopathy and multiple organ dysfunction. Thus, understanding the mechanism of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-induced NET formation would be helpful to reduce thrombosis and prevent ARDS in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. METHODS: We incubated SARS-CoV-2 with neutrophils in the presence or absence of platelets to observe NET formation. We further isolated extracellular vesicles from COVID-19 patients' sera (COVID-19-EVs) to examine their ability to induce NET formation. RESULTS: We demonstrated that antagonistic mAbs against anti-CLEC5A mAb and anti-TLR2 mAb can inhibit COVID-19-EVs-induced NET formation, and generated clec5a-/-/tlr2-/- mice to confirm the critical roles of CLEC5A and TLR2 in SARS-CoV-2-induced lung inflammation in vivo. We found that virus-free extracellular COVID-19 EVs induced robust NET formation via Syk-coupled C-type lectin member 5A (CLEC5A) and TLR2. Blockade of CLEC5A inhibited COVID-19 EVs-induced NETosis, and simultaneous blockade of CLEC5A and TLR2 further suppressed SARS-CoV-2-induced NETosis in vitro. Moreover, thromboinflammation was attenuated dramatically in clec5a-/-/tlr2-/- mice. CONCLUSIONS: This study demonstrates that SARS-CoV-2-activated platelets produce EVs to enhance thromboinflammation via CLEC5A and TLR2, and highlight the importance of CLEC5A and TLR2 as therapeutic targets to reduce the risk of ARDS in COVID-19 patients.


Subject(s)
COVID-19 , Lectins, C-Type , Neutrophils , Pneumonia , Respiratory Distress Syndrome , SARS-CoV-2 , Thrombosis , Animals , Blood Platelets/immunology , Blood Platelets/pathology , Blood Platelets/virology , COVID-19/blood , COVID-19/immunology , Humans , Lectins, C-Type/immunology , Mice , Neutrophils/immunology , Neutrophils/pathology , Neutrophils/virology , Pneumonia/immunology , Pneumonia/pathology , Pneumonia/virology , Receptors, Cell Surface , Respiratory Distress Syndrome/immunology , Respiratory Distress Syndrome/virology , SARS-CoV-2/immunology , Thrombosis/blood , Thrombosis/immunology , Thrombosis/virology , Toll-Like Receptor 2/immunology
4.
Front Immunol ; 13: 732197, 2022.
Article in English | MEDLINE | ID: covidwho-1686479

ABSTRACT

Acute respiratory distress syndrome (ARDS) is a severe pulmonary disease, which is one of the major complications in COVID-19 patients. Dysregulation of the immune system and imbalances in cytokine release and immune cell activation are involved in SARS-CoV-2 infection. Here, the inflammatory, antigen, and auto-immune profile of patients presenting COVID-19-associated severe ARDS has been analyzed using functional proteomics approaches. Both, innate and humoral responses have been characterized through acute-phase protein network and auto-antibody signature. Severity and sepsis by SARS-CoV-2 emerged to be correlated with auto-immune profiles of patients and define their clinical progression, which could provide novel perspectives in therapeutics development and biomarkers of COVID-19 patients. Humoral response in COVID-19 patients' profile separates with significant differences patients with or without ARDS. Furthermore, we found that this profile can be correlated with COVID-19 severity and results more common in elderly patients.


Subject(s)
Autoantigens/immunology , Autoimmunity/immunology , COVID-19/immunology , Respiratory Distress Syndrome/immunology , Respiratory Distress Syndrome/virology , Autoantibodies/immunology , COVID-19/complications , Humans , SARS-CoV-2/immunology
5.
Cell Death Dis ; 13(2): 137, 2022 02 10.
Article in English | MEDLINE | ID: covidwho-1683990

ABSTRACT

Acute respiratory distress syndrome (ARDS) is triggered by various aetiological factors such as trauma, sepsis and respiratory viruses including SARS-CoV-2 and influenza A virus. Immune profiling of severe COVID-19 patients has identified a complex pattern of cytokines including granulocyte macrophage-colony stimulating factor (GM-CSF) and interleukin (IL)-5, which are significant mediators of viral-induced hyperinflammation. This strong response has prompted the development of therapies that block GM-CSF and other cytokines individually to limit inflammation related pathology. The common cytokine binding site of the human common beta (ßc) receptor signals for three inflammatory cytokines: GM-CSF, IL-5 and IL-3. In this study, ßc was targeted with the monoclonal antibody (mAb) CSL311 in engineered mice devoid of mouse ßc and ßIL-3 and expressing human ßc (hßcTg mice). Direct pulmonary administration of lipopolysaccharide (LPS) caused ARDS-like lung injury, and CSL311 markedly reduced lung inflammation and oedema, resulting in improved oxygen saturation levels in hßcTg mice. In a separate model, influenza (HKx31) lung infection caused viral pneumonia associated with a large influx of myeloid cells into the lungs of hßcTg mice. The therapeutic application of CSL311 potently decreased accumulation of monocytes/macrophages, neutrophils, and eosinophils without altering lung viral loads. Furthermore, CSL311 treatment did not limit the viral-induced expansion of NK and NKT cells, or the tissue expression of type I/II/III interferons needed for efficient viral clearance. Simultaneously blocking GM-CSF, IL-5 and IL-3 signalling with CSL311 may represent an improved and clinically applicable strategy to reducing hyperinflammation in the ARDS setting.


Subject(s)
Cytokine Receptor Common beta Subunit/genetics , Cytokine Receptor Common beta Subunit/physiology , Respiratory Distress Syndrome/immunology , Animals , Antibodies, Monoclonal/immunology , Cytokine Receptor Common beta Subunit/immunology , Cytokines , Eosinophils/immunology , Female , Humans , Immunity/genetics , Immunity/physiology , Inflammation/immunology , Leukocytes/metabolism , Male , Mice , Mice, Transgenic , Neutrophils/metabolism , Receptors, Granulocyte-Macrophage Colony-Stimulating Factor , Receptors, Interleukin-3 , Receptors, Interleukin-5 , Respiratory Distress Syndrome/physiopathology
6.
Nat Commun ; 13(1): 383, 2022 01 19.
Article in English | MEDLINE | ID: covidwho-1636827

ABSTRACT

A single center open label phase 2 randomised control trial (Clinical Trial Registry of India No. CTRI/2020/05/025209) was done to assess clinical and immunological benefits of passive immunization using convalescent plasma therapy. At the Infectious Diseases and Beleghata General Hospital in Kolkata, India, 80 patients hospitalized with severe COVID-19 disease and fulfilling the inclusion criteria (aged more than 18 years, with either mild ARDS having PaO2/FiO2 200-300 or moderate ARDS having PaO2/FiO2 100-200, not on mechanical ventilation) were recruited and randomized into either standard of care (SOC) arm (N = 40) or the convalescent plasma therapy (CPT) arm (N = 40). Primary outcomes were all-cause mortality by day 30 of enrolment and immunological correlates of response to therapy if any, for which plasma abundance of a large panel of cytokines was quantitated before and after intervention to assess the effect of CPT on the systemic hyper-inflammation encountered in these patients. The secondary outcomes were recovery from ARDS and time taken to negative viral RNA PCR as well as to report any adverse reaction to plasma therapy. Transfused convalescent plasma was characterized in terms of its neutralizing antibody content as well as proteome. The trial was completed and it was found that primary outcome of all-cause mortality was not significantly different among severe COVID-19 patients with ARDS randomized to two treatment arms (Mantel-Haenszel Hazard Ratio 0.6731, 95% confidence interval 0.3010-1.505, with a P value of 0.3424 on Mantel-Cox Log-rank test). No adverse effect was reported with CPT. In severe COVID-19 patients with mild or moderate ARDS no significant clinical benefit was registered in this clinical trial with convalescent plasma therapy in terms of prespecified outcomes.


Subject(s)
COVID-19/therapy , Antibodies, Neutralizing/immunology , Antibodies, Neutralizing/therapeutic use , Antibodies, Viral/immunology , Antibodies, Viral/therapeutic use , Blood Donors , COVID-19/immunology , COVID-19/virology , Cytokines/blood , Female , Hospitals, General , Humans , Immunity, Humoral , Immunization, Passive , India , Inflammation , Male , Phylogeny , Respiratory Distress Syndrome/immunology , Respiratory Distress Syndrome/therapy , Respiratory Distress Syndrome/virology , SARS-CoV-2/classification , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Survival Analysis , Treatment Outcome , Viral Load
7.
EBioMedicine ; 75: 103809, 2022 Jan.
Article in English | MEDLINE | ID: covidwho-1638088

ABSTRACT

BACKGROUND: Mathematical modelling may aid in understanding the complex interactions between injury and immune response in critical illness. METHODS: We utilize a system biology model of COVID-19 to analyze the effect of altering baseline patient characteristics on the outcome of immunomodulatory therapies. We create example parameter sets meant to mimic diverse patient types. For each patient type, we define the optimal treatment, identify biologic programs responsible for clinical responses, and predict biomarkers of those programs. FINDINGS: Model states representing older and hyperinflamed patients respond better to immunomodulation than those representing obese and diabetic patients. The disparate clinical responses are driven by distinct biologic programs. Optimal treatment initiation time is determined by neutrophil recruitment, systemic cytokine expression, systemic microthrombosis and the renin-angiotensin system (RAS) in older patients, and by RAS, systemic microthrombosis and trans IL6 signalling for hyperinflamed patients. For older and hyperinflamed patients, IL6 modulating therapy is predicted to be optimal when initiated very early (<4th day of infection) and broad immunosuppression therapy (corticosteroids) is predicted to be optimally initiated later in the disease (7th - 9th day of infection). We show that markers of biologic programs identified by the model correspond to clinically identified markers of disease severity. INTERPRETATION: We demonstrate that modelling of COVID-19 pathobiology can suggest biomarkers that predict optimal response to a given immunomodulatory treatment. Mathematical modelling thus constitutes a novel adjunct to predictive enrichment and may aid in the reduction of heterogeneity in critical care trials. FUNDING: C.V. received a Marie Sklodowska Curie Actions Individual Fellowship (MSCA-IF-GF-2020-101028945). R.K.J.'s research is supported by R01-CA208205, and U01-CA 224348, R35-CA197743 and grants from the National Foundation for Cancer Research, Jane's Trust Foundation, Advanced Medical Research Foundation and Harvard Ludwig Cancer Center. No funder had a role in production or approval of this manuscript.


Subject(s)
COVID-19/immunology , Models, Immunological , Respiratory Distress Syndrome/immunology , SARS-CoV-2/immunology , Aged , COVID-19/prevention & control , Clinical Trials as Topic , Female , Humans , Male , Respiratory Distress Syndrome/prevention & control
8.
Signal Transduct Target Ther ; 6(1): 439, 2021 12 24.
Article in English | MEDLINE | ID: covidwho-1585883

ABSTRACT

The development of animal models for COVID-19 is essential for basic research and drug/vaccine screening. Previously reported COVID-19 animal models need to be established under a high biosafety level condition for the utilization of live SARS-CoV-2, which greatly limits its application in routine research. Here, we generate a mouse model of COVID-19 under a general laboratory condition that captures multiple characteristics of SARS-CoV-2-induced acute respiratory distress syndrome (ARDS) observed in humans. Briefly, human ACE2-transgenic (hACE2) mice were intratracheally instilled with the formaldehyde-inactivated SARS-CoV-2, resulting in a rapid weight loss and detrimental changes in lung structure and function. The pulmonary pathologic changes were characterized by diffuse alveolar damage with pulmonary consolidation, hemorrhage, necrotic debris, and hyaline membrane formation. The production of fatal cytokines (IL-1ß, TNF-α, and IL-6) and the infiltration of activated neutrophils, inflammatory monocyte-macrophages, and T cells in the lung were also determined, suggesting the activation of an adaptive immune response. Therapeutic strategies, such as dexamethasone or passive antibody therapy, could effectively ameliorate the disease progression in this model. Therefore, the established mouse model for SARS-CoV-2-induced ARDS in the current study may provide a robust tool for researchers in the standard open laboratory to investigate the pathological mechanisms or develop new therapeutic strategies for COVID-19 and ARDS.


Subject(s)
Angiotensin-Converting Enzyme 2/immunology , COVID-19/immunology , Lung/immunology , Respiratory Distress Syndrome/immunology , SARS-CoV-2/immunology , Angiotensin-Converting Enzyme 2/genetics , Animals , COVID-19/genetics , Disease Models, Animal , Humans , Mice , Mice, Transgenic , Respiratory Distress Syndrome/genetics
9.
JCI Insight ; 7(2)2022 01 25.
Article in English | MEDLINE | ID: covidwho-1575230

ABSTRACT

Acute respiratory distress syndrome (ARDS) is a life-threatening syndrome, constituted by respiratory failure and diffuse alveolar damage that results from dysregulated local and systemic immune activation, causing pulmonary vascular, parenchymal, and alveolar damage. SARS-CoV-2 infection has become the dominant cause of ARDS worldwide, and emerging evidence implicates neutrophils and their cytotoxic arsenal of effector functions as central drivers of immune-mediated lung injury in COVID-19 ARDS. However, key outstanding questions are whether COVID-19 drives a unique program of neutrophil activation or effector functions that contribute to the severe pathogenesis of this pandemic illness and whether this unique neutrophil response can be targeted to attenuate disease. Using a combination of high-dimensional single-cell analysis and ex vivo functional assays of neutrophils from patients with COVID-19 ARDS, compared with those with non-COVID ARDS (caused by bacterial pneumonia), we identified a functionally distinct landscape of neutrophil activation in COVID-19 ARDS that was intrinsically programmed during SARS-CoV-2 infection. Furthermore, neutrophils in COVID-19 ARDS were functionally primed to produce high amounts of neutrophil extracellular traps. Surprisingly, this unique pathological program of neutrophil priming escaped conventional therapy with dexamethasone, thereby revealing a promising target for adjunctive immunotherapy in severe COVID-19.


Subject(s)
COVID-19/immunology , Extracellular Traps/immunology , Neutrophil Activation , Neutrophils/immunology , Respiratory Distress Syndrome/immunology , SARS-CoV-2/immunology , Adult , Aged , Aged, 80 and over , COVID-19/pathology , Female , Humans , Male , Middle Aged , Neutrophils/pathology , Pneumonia, Bacterial/immunology , Pneumonia, Bacterial/pathology , Respiratory Distress Syndrome/pathology , Severity of Illness Index
10.
Viral Immunol ; 34(10): 679-688, 2021 12.
Article in English | MEDLINE | ID: covidwho-1560640

ABSTRACT

The newfound coronavirus disease 2019 (COVID-19), initiated by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is an international public health concern, threatening the lives of millions of people worldwide. The virus seems to have a propensity to infect older males, especially those with underlying diseases. The cytokine storm following hyperactivated immune responses due to SARS-CoV-2 infection is probably the crucial source of severe pneumonia that leads to acute lung injury, systemic inflammatory response syndrome, or acute respiratory distress syndrome, and finally multiple organ dysfunction syndromes, as well as death in many cases. Several studies revealed that interleukin (IL)-1ß levels were elevated during COVID-19 infection. In addition, the IL-1 cytokine family has a pivotal role in the induction of cytokine storm due to uncontrolled immune responses in COVID-19 infection. This article reviews the role of IL-1 in inflammation and utilization of IL-1 inhibitor agents in controlling the inflammatory outcomes initiated by SARS-CoV-2 infection.


Subject(s)
COVID-19/drug therapy , COVID-19/immunology , Cytokine Release Syndrome/drug therapy , Interleukin-1/immunology , Acute Lung Injury/drug therapy , Acute Lung Injury/immunology , Acute Lung Injury/pathology , COVID-19/mortality , COVID-19/pathology , Cytokine Release Syndrome/immunology , Cytokine Release Syndrome/pathology , Humans , Interleukin-1/antagonists & inhibitors , Multiple Organ Failure/drug therapy , Multiple Organ Failure/immunology , Multiple Organ Failure/pathology , Respiratory Distress Syndrome/drug therapy , Respiratory Distress Syndrome/immunology , Respiratory Distress Syndrome/pathology , SARS-CoV-2/immunology , SARS-CoV-2/pathogenicity
11.
Front Immunol ; 12: 753849, 2021.
Article in English | MEDLINE | ID: covidwho-1523705

ABSTRACT

Background: CD14+ monocytes present antigens to adaptive immune cells via monocytic human leukocyte antigen receptor (mHLA-DR), which is described as an immunological synapse. Reduced levels of mHLA-DR can display an acquired immune defect, which is often found in sepsis and predisposes for secondary infections and fatal outcomes. Monocytic HLA-DR expression is reliably induced by interferon- γ (IFNγ) therapy. Case Report: We report a case of multidrug-resistant superinfected COVID-19 acute respiratory distress syndrome (ARDS) on extracorporeal membrane oxygenation (ECMO) support. The resistance profiles of the detected Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii and Citrobacter freundii isolates were equipped with resistance to all four antibiotic classes including carbapenems (4MRGN) and Cefiderocol in the case of K. pneumoniae. A causal therapeutic antibiotic strategy was not available. Therefore, we measured the immune status of the patient aiming to identify a potential acquired immune deficiency. Monocyte HLA-DR expression identified by FACS analysis revealed an expression level of 34% positive monocytes and suggested severe immunosuppression. We indicated IFNγ therapy, which resulted in a rapid increase in mHLA-DR expression (96%), rapid resolution of invasive bloodstream infection, and discharge from the hospital on day 70. Discussion: Superinfection is a dangerous complication of COVID-19 pneumonia, and sepsis-induced immunosuppression is a risk factor for it. Immunosuppression is expressed by a disturbed antigen presentation of monocytes to cells of the adaptive immune system. The case presented here is remarkable as no validated antibiotic regimen existed against the detected bacterial pathogens causing bloodstream infection and severe pneumonia in a patient suffering from COVID-19 ARDS. Possible restoration of the patient's own immunity by IFNγ was a plausible option to boost the patient's immune system, eliminate the identified 4MRGNs, and allow for lung recovery. This led to the conclusion that immune status monitoring is useful in complicated COVID-19-ARDS and that concomitant IFNγ therapy may support antibiotic strategies. Conclusion: After a compromised immune system has been detected by suppressed mHLA-DR levels, the immune system can be safely reactivated by IFNγ.


Subject(s)
Bacteria/immunology , COVID-19/immunology , Drug Resistance, Multiple/immunology , HLA Antigens/immunology , Interferon-gamma/immunology , Monocytes/immunology , Respiratory Distress Syndrome/immunology , Adult , Humans , Receptors, Interferon/immunology
12.
Front Immunol ; 12: 738093, 2021.
Article in English | MEDLINE | ID: covidwho-1518484

ABSTRACT

Disease caused by SARS-CoV-2 coronavirus (COVID-19) led to significant morbidity and mortality worldwide. A systemic hyper-inflammation characterizes severe COVID-19 disease, often associated with acute respiratory distress syndrome (ARDS). Blood biomarkers capable of risk stratification are of great importance in effective triage and critical care of severe COVID-19 patients. Flow cytometry and next-generation sequencing were done on peripheral blood cells and urokinase-type plasminogen activator receptor (suPAR), and cytokines were measured from and mass spectrometry-based proteomics was done on plasma samples from an Indian cohort of COVID-19 patients. Publicly available single-cell RNA sequencing data were analyzed for validation of primary data. Statistical analyses were performed to validate risk stratification. We report here higher plasma abundance of suPAR, expressed by an abnormally expanded myeloid cell population, in severe COVID-19 patients with ARDS. The plasma suPAR level was found to be linked to a characteristic plasma proteome, associated with coagulation disorders and complement activation. Receiver operator characteristic curve analysis to predict mortality identified a cutoff value of suPAR at 1,996.809 pg/ml (odds ratio: 2.9286, 95% confidence interval 1.0427-8.2257). Lower-than-cutoff suPAR levels were associated with a differential expression of the immune transcriptome as well as favorable clinical outcomes, in terms of both survival benefit (hazard ratio: 0.3615, 95% confidence interval 0.1433-0.912) and faster disease remission in our patient cohort. Thus, we identified suPAR as a key pathogenic circulating molecule linking systemic hyperinflammation to the hypercoagulable state and stratifying clinical outcomes in severe COVID-19 patients with ARDS.


Subject(s)
COVID-19/blood , Receptors, Urokinase Plasminogen Activator/blood , SARS-CoV-2 , Adult , Aged , Blood Coagulation Disorders/blood , Blood Coagulation Disorders/immunology , Blood Proteins/analysis , COVID-19/immunology , Cytokines/blood , Humans , Inflammation/blood , Inflammation/immunology , Middle Aged , Myeloid Cells/immunology , Proteome/analysis , Randomized Controlled Trials as Topic , Respiratory Distress Syndrome/blood , Respiratory Distress Syndrome/immunology , Severity of Illness Index , Young Adult
13.
Nat Med ; 28(1): 201-211, 2022 01.
Article in English | MEDLINE | ID: covidwho-1517637

ABSTRACT

Although critical for host defense, innate immune cells are also pathologic drivers of acute respiratory distress syndrome (ARDS). Innate immune dynamics during Coronavirus Disease 2019 (COVID-19) ARDS, compared to ARDS from other respiratory pathogens, is unclear. Moreover, mechanisms underlying the beneficial effects of dexamethasone during severe COVID-19 remain elusive. Using single-cell RNA sequencing and plasma proteomics, we discovered that, compared to bacterial ARDS, COVID-19 was associated with expansion of distinct neutrophil states characterized by interferon (IFN) and prostaglandin signaling. Dexamethasone during severe COVID-19 affected circulating neutrophils, altered IFNactive neutrophils, downregulated interferon-stimulated genes and activated IL-1R2+ neutrophils. Dexamethasone also expanded immunosuppressive immature neutrophils and remodeled cellular interactions by changing neutrophils from information receivers into information providers. Male patients had higher proportions of IFNactive neutrophils and preferential steroid-induced immature neutrophil expansion, potentially affecting outcomes. Our single-cell atlas (see 'Data availability' section) defines COVID-19-enriched neutrophil states and molecular mechanisms of dexamethasone action to develop targeted immunotherapies for severe COVID-19.


Subject(s)
COVID-19/immunology , Cytokines/immunology , Dexamethasone/therapeutic use , Glucocorticoids/therapeutic use , Neutrophils/immunology , Pneumonia, Bacterial/immunology , Respiratory Distress Syndrome/immunology , Adult , Aged , COVID-19/complications , COVID-19/drug therapy , COVID-19/genetics , Cell Communication , Chromatography, Liquid , Down-Regulation , Female , Gene Regulatory Networks , Humans , Immunity, Innate/immunology , Interferons/immunology , Male , Middle Aged , Neutrophils/metabolism , Pneumonia, Bacterial/complications , Pneumonia, Bacterial/drug therapy , Pneumonia, Bacterial/genetics , Prostaglandins/immunology , Proteomics , RNA-Seq , Respiratory Distress Syndrome/drug therapy , Respiratory Distress Syndrome/etiology , Respiratory Distress Syndrome/genetics , SARS-CoV-2 , Severity of Illness Index , Sex Factors , Single-Cell Analysis , Tandem Mass Spectrometry
14.
Nat Immunol ; 23(1): 62-74, 2022 01.
Article in English | MEDLINE | ID: covidwho-1514418

ABSTRACT

The molecular mechanisms governing orderly shutdown and retraction of CD4+ type 1 helper T (TH1) cell responses remain poorly understood. Here we show that complement triggers contraction of TH1 responses by inducing intrinsic expression of the vitamin D (VitD) receptor and the VitD-activating enzyme CYP27B1, permitting T cells to both activate and respond to VitD. VitD then initiated the transition from pro-inflammatory interferon-γ+ TH1 cells to suppressive interleukin-10+ cells. This process was primed by dynamic changes in the epigenetic landscape of CD4+ T cells, generating super-enhancers and recruiting several transcription factors, notably c-JUN, STAT3 and BACH2, which together with VitD receptor shaped the transcriptional response to VitD. Accordingly, VitD did not induce interleukin-10 expression in cells with dysfunctional BACH2 or STAT3. Bronchoalveolar lavage fluid CD4+ T cells of patients with COVID-19 were TH1-skewed and showed de-repression of genes downregulated by VitD, from either lack of substrate (VitD deficiency) and/or abnormal regulation of this system.


Subject(s)
Interferon-gamma/immunology , Interleukin-10/immunology , SARS-CoV-2/immunology , Th1 Cells/immunology , Vitamin D/metabolism , 25-Hydroxyvitamin D3 1-alpha-Hydroxylase/metabolism , Basic-Leucine Zipper Transcription Factors/metabolism , Bronchoalveolar Lavage Fluid/cytology , COVID-19/immunology , COVID-19/pathology , Complement C3a/immunology , Complement C3b/immunology , Humans , JNK Mitogen-Activated Protein Kinases/metabolism , Lymphocyte Activation/immunology , Receptors, Calcitriol/metabolism , Respiratory Distress Syndrome/immunology , Respiratory Distress Syndrome/pathology , Respiratory Distress Syndrome/virology , STAT3 Transcription Factor/metabolism , Signal Transduction/immunology , Transcription, Genetic/genetics
16.
Front Immunol ; 12: 752612, 2021.
Article in English | MEDLINE | ID: covidwho-1456293

ABSTRACT

Background: Lymphopenia and the neutrophil/lymphocyte ratio may have prognostic value in COVID-19 severity. Objective: We investigated neutrophil subsets and functions in blood and bronchoalveolar lavage (BAL) of COVID-19 patients on the basis of patients' clinical characteristics. Methods: We used a multiparametric cytometry profiling based to mature and immature neutrophil markers in 146 critical or severe COVID-19 patients. Results: The Discovery study (38 patients, first pandemic wave) showed that 80% of Intensive Care Unit (ICU) patients develop strong myelemia with CD10-CD64+ immature neutrophils (ImNs). Cellular profiling revealed three distinct neutrophil subsets expressing either the lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), the interleukin-3 receptor alpha (CD123), or programmed death-ligand 1 (PD-L1) overrepresented in ICU patients compared to non-ICU patients. The proportion of LOX-1- or CD123-expressing ImNs is positively correlated with clinical severity, cytokine storm (IL-1ß, IL-6, IL-8, TNFα), acute respiratory distress syndrome (ARDS), and thrombosis. BALs of patients with ARDS were highly enriched in LOX-1-expressing ImN subsets and in antimicrobial neutrophil factors. A validation study (118 patients, second pandemic wave) confirmed and strengthened the association of the proportion of ImN subsets with disease severity, invasive ventilation, and death. Only high proportions of LOX-1-expressing ImNs remained strongly associated with a high risk of severe thrombosis independently of the plasma antimicrobial neutrophil factors, suggesting an independent association of ImN markers with their functions. Conclusion: LOX-1-expressing ImNs may help identifying COVID-19 patients at high risk of severity and thrombosis complications.


Subject(s)
COVID-19/complications , Neutrophils/immunology , Scavenger Receptors, Class E/genetics , Thrombosis/etiology , Adult , Aged , B7-H1 Antigen/genetics , B7-H1 Antigen/immunology , Bronchoalveolar Lavage Fluid/immunology , COVID-19/genetics , COVID-19/immunology , COVID-19/virology , Critical Illness , Female , Humans , Interleukin-3 Receptor alpha Subunit/genetics , Interleukin-3 Receptor alpha Subunit/immunology , Interleukin-8/genetics , Interleukin-8/immunology , Male , Middle Aged , Respiratory Distress Syndrome/etiology , Respiratory Distress Syndrome/genetics , Respiratory Distress Syndrome/immunology , SARS-CoV-2/physiology , Scavenger Receptors, Class E/immunology , Thrombosis/genetics , Thrombosis/immunology
17.
J Clin Invest ; 130(11): 6151-6157, 2020 11 02.
Article in English | MEDLINE | ID: covidwho-1435146

ABSTRACT

Emerging data indicate that complement and neutrophils contribute to the maladaptive immune response that fuels hyperinflammation and thrombotic microangiopathy, thereby increasing coronavirus 2019 (COVID-19) mortality. Here, we investigated how complement interacts with the platelet/neutrophil extracellular traps (NETs)/thrombin axis, using COVID-19 specimens, cell-based inhibition studies, and NET/human aortic endothelial cell (HAEC) cocultures. Increased plasma levels of NETs, tissue factor (TF) activity, and sC5b-9 were detected in patients. Neutrophils of patients yielded high TF expression and released NETs carrying active TF. Treatment of control neutrophils with COVID-19 platelet-rich plasma generated TF-bearing NETs that induced thrombotic activity of HAECs. Thrombin or NETosis inhibition or C5aR1 blockade attenuated platelet-mediated NET-driven thrombogenicity. COVID-19 serum induced complement activation in vitro, consistent with high complement activity in clinical samples. Complement C3 inhibition with compstatin Cp40 disrupted TF expression in neutrophils. In conclusion, we provide a mechanistic basis for a pivotal role of complement and NETs in COVID-19 immunothrombosis. This study supports strategies against severe acute respiratory syndrome coronavirus 2 that exploit complement or NETosis inhibition.


Subject(s)
Betacoronavirus , Complement Membrane Attack Complex , Coronavirus Infections , Extracellular Traps , Neutrophils , Pandemics , Pneumonia, Viral , Thromboplastin , Thrombosis , Aged , Betacoronavirus/immunology , Betacoronavirus/metabolism , COVID-19 , Complement Activation/drug effects , Complement Membrane Attack Complex/immunology , Complement Membrane Attack Complex/metabolism , Coronavirus Infections/blood , Coronavirus Infections/immunology , Extracellular Traps/immunology , Extracellular Traps/metabolism , Female , Humans , Male , Middle Aged , Neutrophils/immunology , Neutrophils/metabolism , Peptides, Cyclic/pharmacology , Pneumonia, Viral/blood , Pneumonia, Viral/immunology , Receptor, Anaphylatoxin C5a/antagonists & inhibitors , Receptor, Anaphylatoxin C5a/blood , Receptor, Anaphylatoxin C5a/immunology , Respiratory Distress Syndrome/blood , Respiratory Distress Syndrome/immunology , Respiratory Distress Syndrome/virology , SARS-CoV-2 , Thrombin/immunology , Thrombin/metabolism , Thromboplastin/immunology , Thromboplastin/metabolism , Thrombosis/blood , Thrombosis/immunology , Thrombosis/virology
18.
Nat Commun ; 12(1): 5152, 2021 08 26.
Article in English | MEDLINE | ID: covidwho-1376195

ABSTRACT

The immunological features that distinguish COVID-19-associated acute respiratory distress syndrome (ARDS) from other causes of ARDS are incompletely understood. Here, we report the results of comparative lower respiratory tract transcriptional profiling of tracheal aspirate from 52 critically ill patients with ARDS from COVID-19 or from other etiologies, as well as controls without ARDS. In contrast to a "cytokine storm," we observe reduced proinflammatory gene expression in COVID-19 ARDS when compared to ARDS due to other causes. COVID-19 ARDS is characterized by a dysregulated host response with increased PTEN signaling and elevated expression of genes with non-canonical roles in inflammation and immunity. In silico analysis of gene expression identifies several candidate drugs that may modulate gene expression in COVID-19 ARDS, including dexamethasone and granulocyte colony stimulating factor. Compared to ARDS due to other types of viral pneumonia, COVID-19 is characterized by impaired interferon-stimulated gene (ISG) expression. The relationship between SARS-CoV-2 viral load and expression of ISGs is decoupled in patients with COVID-19 ARDS when compared to patients with mild COVID-19. In summary, assessment of host gene expression in the lower airways of patients reveals distinct immunological features of COVID-19 ARDS.


Subject(s)
COVID-19/genetics , RNA/genetics , Respiratory Distress Syndrome/genetics , Trachea/immunology , Adult , Aged , Aged, 80 and over , COVID-19/immunology , COVID-19/virology , Case-Control Studies , Cohort Studies , Critical Illness , Cytokines/genetics , Cytokines/immunology , Female , Gene Expression Profiling , Humans , Male , Middle Aged , RNA/metabolism , Respiratory Distress Syndrome/immunology , Respiratory Distress Syndrome/virology , SARS-CoV-2/physiology , Sequence Analysis, RNA
19.
Front Immunol ; 12: 726909, 2021.
Article in English | MEDLINE | ID: covidwho-1359195

ABSTRACT

Mesenchymal stem cells (MSCs) have been widely used in preclinical and clinical trials for various diseases and have shown great potential in the treatment of sepsis and coronavirus disease (COVID-19). Inflammatory factors play vital roles in the pathogenesis of diseases. The interaction between inflammatory factors is extremely complex. Once the dynamics of inflammatory factors are unbalanced, inflammatory responses and cytokine storm syndrome develop, leading to disease exacerbation and even death. Stem cells have become ideal candidates for the treatment of such diseases due to their immunosuppressive and anti-inflammatory properties. However, the mechanisms by which stem cells affect inflammation and immune regulation are still unclear. This article discusses the therapeutic mechanism and potential value of MSCs in the treatment of sepsis and the novel COVID-19, outlines how MSCs mediate innate and acquired immunity at both the cellular and molecular levels, and described the anti-inflammatory mechanisms and related molecular pathways. Finally, we review the safety and efficacy of stem cell therapy in these two diseases at the preclinical and clinical levels.


Subject(s)
COVID-19/therapy , Cytokine Release Syndrome/therapy , Mesenchymal Stem Cell Transplantation , Mesenchymal Stem Cells/immunology , SARS-CoV-2/immunology , COVID-19/immunology , COVID-19/pathology , Cell- and Tissue-Based Therapy/methods , Cytokine Release Syndrome/immunology , Cytokine Release Syndrome/pathology , Humans , Respiratory Distress Syndrome/immunology , Respiratory Distress Syndrome/pathology , Respiratory Distress Syndrome/prevention & control
20.
J Infect Dis ; 224(4): 565-574, 2021 08 16.
Article in English | MEDLINE | ID: covidwho-1358458

ABSTRACT

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), causing coronavirus disease 2019 (COVID-19), has led to significant morbidity and mortality. While most suffer from mild symptoms, some patients progress to severe disease with acute respiratory distress syndrome (ARDS) and associated systemic hyperinflammation. METHODS: First, to characterize key cytokines and their dynamics in this hyperinflammatory condition, we assessed abundance and correlative expression of a panel of 48 cytokines in patients progressing to ARDS as compared to patients with mild disease. Then, in an ongoing randomized controlled trial of convalescent plasma therapy (CPT), we analyzed rapid effects of CPT on the systemic cytokine dynamics as a correlate for the level of hypoxia experienced by the patients. RESULTS: We identified an anti-inflammatory role of CPT independent of its neutralizing antibody content. CONCLUSIONS: Neutralizing antibodies, as well as reductions in circulating interleukin-6 and interferon-γ-inducible protein 10, contributed to marked rapid reductions in hypoxia in response to CPT. CLINICAL TRIAL REGISTRY OF INDIA: CTRI/2020/05/025209. http://www.ctri.nic.in/.


Subject(s)
COVID-19/immunology , COVID-19/therapy , SARS-CoV-2/immunology , Adult , Anti-Inflammatory Agents/therapeutic use , Antibodies, Neutralizing/immunology , COVID-19/drug therapy , COVID-19/epidemiology , COVID-19/virology , Cytokines/blood , Cytokines/immunology , Female , Humans , Immunization, Passive/methods , India/epidemiology , Male , Middle Aged , Plasma , RNA, Viral/isolation & purification , Respiratory Distress Syndrome/drug therapy , Respiratory Distress Syndrome/immunology , SARS-CoV-2/isolation & purification , Viral Load
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